The present invention relates to improvements in precast concrete constructions useful in the erection of modular prefabricated concrete structures.
Concrete constructions of precast structural elements are used for erecting low-cost concrete structures, such as buildings, houses, walls, etc. Such structures are generally more economically and more easily erected than structures constructed with conventional building techniques. These advantages may be offset, however, if special tools or equipment are required to assemble the precast elements, or if very close control over tolerances is required, such as in the positioning of supporting foundations. The more structural elements which can be prefabricated, and hence the less custom construction required on the building site, the more efficient the construction becomes. Moreover, less skilled labor is required for erecting a structure when most of the structural elements are precast.
Prefabricated constructions are known. For example, Hughes U.S. Pat. No. 3,350,826; Nov. 7, 1967, discloses a method of construction including a precast concrete wall held in slots in poured footings and precast upper beams and columns. Connection of the wall to the upper beams and the footings is by means of reinforcing bars imbedded in the wall which are grouted into openings in the beams and the footings. Trezzini U.S. Pat. No. et al. 3,693,308; Sept. 26, 1972, discloses precast wall panels connected to spaced, notched supporting blocks by pins extending between aligned holes in the blocks and the panels. Adjacent wall panels are connected together by reinforcing bars and concrete poured into spaces between adjacent panels. Hammond U.S. Pat. No. 3,490,186; Jan. 20, 1970, discloses grooved columns supported on spaced footing pads and attached thereto by dowels extending from the pads into the columns. A wall panel, which extends between the columns, fits into the column grooves. The walls are tied together at their tops by metal sheaths. After erection of the columns and the walls, a concrete grade beam is poured under the walls for support.
The known precast concrete constructions do not maximize the number of precast structural elements, nor minimize the on-site conventional construction and skilled labor requirements. It is desirable to provide precast concrete constructions having these advantages.